Most jobs in the bay area are 6-7 day a week jobs. You may not be logged in to Slack on Saturday and Sunday but you're monitoring email or on the look out for PagerDuty.
I’ve been working in the Bay for over a decade and this is what an on-call rotation is for. If you’re doing this every week and are not a founder quit your job.
Rotation helps, but as a more senior/experienced person on the team it's easy for things to be "elevated" up to you because person X couldn't figure it out, etc.
This should be a rare event. If it’s not it’s also a sign of immaturity and disorder. Not worth it, especially as a senior engineer.